1. Field of the Invention
The present invention relates to a standby voltage boosting stage and method for a memory device.
2. Discussion of the Related Art
Voltage boosters are currently designed to operate in one of several paradigms. In a first paradigm, the booster only operates when the device is active (not on standby); in a second paradigm, the booster also operates in regulating mode when the device is on standby (i.e., a regulating device monitors the voltage on the output boost line of the pump, and enables or disables the pump accordingly); and in a third paradigm, the booster operates in free-running mode (with no regulation) but at low frequency also when the device is on standby.
None of the above paradigms is without drawbacks. The first paradigm has a slow response during reading after being on stand-by; the second paradigm, while solving the slow response problem, presents the drawback of high power consumption, which is unacceptable in most applications; and the third paradigm, while also solving the slow response problem, only partly solves the problem of high power consumption. Though acceptable at low supply voltages, in which case, a circuit ready to switch from standby is preferable to a circuit with no stand-by power consumption, the third solution is unacceptable with standard supply voltages (5 V), in which case, power consumption of the pump may be unnecessarily increased or unacceptably high.
Moreover, being specially designed and implemented for low-voltage devices (typically 3 V), all of the above paradigms are rigid and unadaptable to other voltage levels.